1. Field of the Invention
The present invention relates to an image processing device, an image processing method, and an imaging device.
2. Description of the Related Art
A so-called 1CCD imaging device as one of full-color imaging devices is suitable for consumer apparatuses required to be reduced in size and cost such as a digital still camera (DSC) and a cellular phone with camera. In the 1CCD imaging device, any one of color filters for red (R), green (G), and blue (B) is provided on a photoelectric element and a sensitivity signal of an insufficient color component is calculated for each of pixel positions to obtain image signals for a plurality of colors from one two-dimensional imaging element. A sensitivity level value of the insufficient color component is generated by interpolating sensitivity level values of pixels present around a pixel of attention. For example, Japanese Patent Application Laid-Open No. 2001-197512 proposes a technology for assuming a geometric figure in a three-dimensional space and generating, based on a segment homothetic ratio of the geometric figure, a sensitivity level value of an insufficient color component.
For example, when a pixel for R, an acquired color component of which is an R component, is set as a pixel of attention, a sensitivity level value of an insufficient color component is calculated by assuming a geometric figure similar to a geometric figure having, as vertexes, a sensitivity level value of the pixel of attention and sensitivity level values of pixels for R present around the pixel of attention. In the case of the Bayer array known in the past as a pixel array of 1CCD two-dimensional imaging elements, the sensitivity level value of the insufficient color component can be calculated by assuming pyramids as the geometric figures similar to each other irrespectively of whether the pixel of attention is the pixel for R or the pixel for B. On the other hand, when the pixel of attention is the pixel for G, because an array of pixels for G is different from those of pixels for R and pixels for B, the sensitivity level value of the insufficient color component is calculated by assuming a triangle as the geometric figures similar to each other. In this way, different geometric figures are assumed according to the acquired color component of the pixel of attention. Therefore, in some case, a difference occurs in accuracy of an arithmetic operation for the sensitivity level value of the insufficient color component. When the triangle is used as the geometric figures, the number of pixels, sensitivity level values of which are referred to, is small compared with that in the case of the pyramid. Therefore, R light and B light having low sensitivity compared with G light are interpolated with a smaller number of data. Consequently, the interpolation tends to be affected by output fluctuation in the pixels and the accuracy is further deteriorated.